The present invention relates generally to plugs for sealing holes, and, more particularly, to plugs for sealing holes drilled through the interior or exterior wall surface of a house or mobile home during, for example, the installation of insulation materials.
Over the past few years the technique of blowing in insulation through holes drilled in the walls of houses and mobile homes has become very popular as a convenient way to insulate an uninsulated structure or to add additional insulation. This technique requires the drilling of a series of holes in either an interior or exterior wall, blowing in insulation and then sealing the holes with a patch or plug after installation of the insulation. For the sake of simplicity and convenience, the holes are usually drilled in the exterior wall and plugs are used to close them. A serious problem occurs with sealing exterior wall holes with plugs as the plugs now used permit the entrance of water past the plug and into the insulated wall. As a result of the plug leaking, the installed insulation soon becomes wet, whereupon it loses its insulation value and, in cold weather, freezes thereby forming a block of ice-encased insulation between the interior and exterior walls of the insulated structure.
In addition to losing its insulation value, wet insulation, particularly cellulose, also loses much of its fire retardency capability, thus providing the potential for a serious tragedy should a fire occur. If foam insulation is used, the entering water can cause it to shrink and separate and create an unattractive chemical residue which can pass through the leaking plug and drip down an exterior wall. The entrance of water also causes a settling of the insulation leaving gaps of uninsulated areas in the wall and further results in the warping and rotting of the wood framing members used to construct the walls. Thus, over a period of years subsequent to an insulation job, major structural damage can result.
Conventional plugs are also retained in place by a simple force fit of a projecting portion of a plug into the hole often producing a loose fit which is insufficient to retain a plug in place, particularly after water seeps into the interior wall and the structural wall support members begin to warp and rot or wet insulation begins to dry out. In addition, the installed compacted insulation presses against the projecting portion of a plug further inhibiting long term retention of a plug in place. Conventional plugs are also designed to fit in a perfectly drilled hole; consequently, if the hole is not properly drilled, the plugs will not be reliably retained in place. Accordingly, after insulation conventional plugs often project away from a sealed exterior wall surface by a quarter of an inch or more and in some instances the plugs fall out. This further aggravates the problem of preventing ingress of water into the interior of an unsulated wall.
The fluid leakage problems are particularly acute in a mobile home having a flat roof and an exterior siding which consists solely of an aluminum sheet which runs from floor to ceiling. If the hole is drilled at a relatively high position on the exterior siding and water enters because of an insufficient sealing of the plug to the exterior surface, this water will run all the way down the interior side of the aluminum sheet wetting all adjacent insulation. If a hole is drilled in the roof and an installed plug leaks, the entering water can ruin an interior ceiling and roof support in addition to the installed insulation.